Moving Cellular Material

Chapter 2, Lesson 3

Membranes• Control the movement of materials in and out of

cell.– Semipermeable – only certain substances can pass

through.– There are many different ways for a substance to pass

through the membrane.• Process depends on the physical and chemical properties of

the substance.

Passive Transport• The movement of substances through a cell

membrane– No energy– Usually small molecules (O2 and CO2)

– Depends on the amount of substances on each side of the membrane.

Diffusion• The movement of substances from an area of

higher concentration to an area of lower concentration.

Passive Transport - Osmosis

The diffusion of water molecules through a selectively permeable membrane. (No energy required)

Red Blood Cells

Facilitated Diffusion

• When molecules pass through a cell membrane using special proteins called transport proteins.

Active TransportThe movement of materials through a cell membrane using energy. (Moves from low to high concentration)

Endocytosis

• The process during which a cell takes in a substance by surrounding it with the cell membrane.

Exocytosis

• The process during which a cell’s vesicles release their contents outside the cell.